Green’s Dictionary of Slang

fullie n.

also fully
[SE fully automatic]

(US gang) an automatic weapon, e.g. an Uzi, Glock or Tech Nine, as used in gang wars.

[US]K. Scott Monster (1994) 382: Other parts of South Central are still conducting their ‘ralks’ with fullies, body armor and pagers.
[US]Mack 10 ‘Mack 10’s The Name’ [lyrics] Let Me Ride on these niggaz, check em nine double-m fully tech em / Straight up gun play one way, rat-a-tat-tat em / Buck red hot ones at em, aim at em, flame at pop-um.